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Update documentation

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Signed-off-by: Tom Eastep <teastep@shorewall.net>
This commit is contained in:
Tom Eastep 2011-11-19 15:18:43 -08:00
parent ae8aa3a45a
commit 83d7cfa76a
8 changed files with 264 additions and 14 deletions
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2
Shorewall/Perl/Shorewall/Zones.pm
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@ -444,7 +444,7 @@ sub process_zone( \$ ) {
$type = IPSEC;
} elsif ( $type =~ /^bport([46])?$/i ) {
fatal_error "Invalid zone type ($type)" if $1 && $1 != $family;
warning_message "Bridge Port zones should have a parent zone" unless @parents;
warning_message "Bridge Port zones should have a parent zone" unless @parents || $config{ZONE_BITS};
$type = BPORT;
push @bport_zones, $zone;
} elsif ( $type eq 'firewall' ) {

218
docs/bridge-Shorewall-perl.xml
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@ -770,6 +770,224 @@ ACCEPT $FW $DMZ tcp 53 </
</orderedlist>
</section>
<section id="veth">
<title>Using Back-to-back veth Devices to Interface with a Bridge</title>
<para>Beginning with Shorewall 4.4.26, Shorewall has limited support for
using back-to-back veth devices to interface with a bridge. This approach
has the advantage that traffic between any pair of zones can be filtered.
The disadvantage is the complexity of the approach.</para>
<para>This configuration is shown in the following diagram.</para>
<graphic align="center" fileref="images/veth1.png" />
<para>In this configuration, veth0 is assigned the internal IP address;
br0 does not have an IP address.</para>
<para>Traffic from the <emphasis role="bold">net</emphasis> and <emphasis
role="bold">fw</emphasis> zones to the <emphasis
role="bold">zone<emphasis>i</emphasis></emphasis> zones goes thru
veth0-&gt;veth1-&gt;ethN-&gt;. Traffic from the <emphasis
role="bold">zone<emphasis>i</emphasis></emphasis> zones to the <emphasis
role="bold">fw</emphasis> and <emphasis role="bold">net</emphasis> zones
takes the reverse path: ethN-&gt;veth1-&gt;veth0. As a consequence,
traffic between <emphasis role="bold">net</emphasis>,<emphasis
role="bold">fw</emphasis> and <emphasis
role="bold">zone<emphasis>i</emphasis></emphasis> goes through Netfilter
twice: once in the routed firewall (eth0,veth0) and once in the bridged
firewall (eth1,eth2,eth3,veth1).</para>
<para>The back-to-back veth devices (veth0 and veth1) are created using
this command:</para>
<programlisting>ip link add type veth</programlisting>
<para>If you have veth devices and want to assign specific names to the
created devices, use this format:</para>
<programlisting>ip link add name FOO type veth peer name BAR</programlisting>
<para>Here's an /etc/network/interfaces stanza that configures veth0,
veth1 and the bridge:</para>
<programlisting>auto veth0
iface veth0 inet static
address 10.10.10.1
netmask 255.255.255.0
network 10.10.10.0
broadcast 10.10.10.255
pre-up /sbin/ip link add name veth0 type veth peer name veth1
pre-up /sbin/ip link set eth1 up
pre-up /sbin/ip link set eth2 up
pre-up /sbin/ip link set eth3 up
pre-up /sbin/ip link set veth1 up
pre-up /usr/sbin/brctl addbr br0
pre-up /usr/sbin/brctl addif br0 eth1
pre-up /usr/sbin/brctl addif br0 eth2
pre-up /usr/sbin/brctl addif br0 eth3
pre-up /usr/sbin/brctl addif br0 veth1
pre-down /usr/sbin/brctl delif br0 eth1
pre-down /sbin/ip link set eth2 down
pre-down /usr/sbin/brctl delif br0 eth2
pre-down /sbin/ip link set eth2 down
pre-down /usr/sbin/brctl delif br0 eth3
pre-down /sbin/ip link set eth3 down
pre-down /usr/sbin/brctl delif br0 veth1
pre-down /sbin/ip link set veth1 down
post-down /usr/sbin/brctl delbr br0
post-down /sbin/ip link del veth0</programlisting>
<para>In <ulink url="manpages/shorewall.net.html">shorewall.conf</ulink>
(5), we need this:</para>
<programlisting>ZONE_BITS=3</programlisting>
<para>This does two things:</para>
<orderedlist>
<listitem>
<para>It enables <firstterm>automatic packet
marking</firstterm>.</para>
</listitem>
<listitem>
<para>It allows up to 8 <replaceable>marked</replaceable> zones
(2**3). Zones are marked unless they have <option>nomark</option> in
the OPTIONS column of their entry in <ulink
url="manpages/shorewall-zones.html">shorewall-zones </ulink>(5).
Packets originating in a marked zone have a mark assigned
automatically by Shorewall.</para>
</listitem>
</orderedlist>
<para>For this configuration, we need several additional zones as shown
here:</para>
<programlisting>#ZONE TYPE OPTIONS IN OUT
# OPTIONS OPTIONS
fw firewall
net ipv4
zone1 bport
zone2 bport
zone3 bport
<emphasis role="bold">loc ipv4 nomark
col ipv4 nomark</emphasis></programlisting>
<note>
<para><emphasis role="bold">col</emphasis> is <emphasis
role="bold">loc</emphasis> spelled backward.</para>
</note>
<programlisting>#ZONE INTERFACES BROADCAST OPTIONS
net eth0 ...
- br0 ...
zone1 br0:eth1 ...
zone2 br0:eth2 ...
zone3 br0:eth3 ...
loc veth0 ...
col br0:veth1 ...</programlisting>
<para>Several things to note here</para>
<orderedlist>
<listitem>
<para>We have defined two unmarked zones: <emphasis
role="bold">loc</emphasis> and <emphasis role="bold">col</emphasis>.
This allows traffic from the <emphasis
role="bold">zone</emphasis><emphasis><emphasis
role="bold">i</emphasis></emphasis> zones to the fw and net zones to
retain the mark of their originating bport zones. It also allows
traffic from the <emphasis role="bold">fw</emphasis> and <emphasis
role="bold">net</emphasis> zones to the <emphasis
role="bold">zonei</emphasis> zones to retain the <emphasis
role="bold">fw</emphasis> and <emphasis role="bold">net</emphasis>
marks respectively.</para>
</listitem>
<listitem>
<para>That means that traffic entering the bridge on veth1 will have a
different mark value, depending on whether it originated in the
<emphasis role="bold">net</emphasis> zone or in the <emphasis
role="bold">fw</emphasis> zone.</para>
</listitem>
<listitem>
<para>Similarly, traffic arriving on the veth0 interface will have a
mark that indicates which of the <emphasis
role="bold">zonei</emphasis> zones each packet originated on.</para>
</listitem>
</orderedlist>
<para>The basic idea here is that we want to filter traffic to the
<emphasis role="bold">zonei</emphasis> zones as it leaves veth1 and we
want to filter traffic from those zones as it leaves veth0. So we use this
type of polices:</para>
<programlisting>#SOURCE DEST POLICY
fw loc ACCEPT
net loc ACCEPT
net all DROP:info
zone1 col ACCEPT
zone2 col ACCEPT
zone3 col ACCEPT
all all REJECT:info</programlisting>
<para>Rules allowing traffic from the net to zone2 look like this:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/ MARK
# PORT(S) PORT(S) DEST LIMIT GROUP
ACCEPT col zone2 tcp 22 - - - - <emphasis
role="bold">net</emphasis></programlisting>
<para>or more compactly:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST
# PORT(S)
ACCEPT col <emphasis role="bold">zone2</emphasis> tcp 22 ; mark=<emphasis
role="bold">net</emphasis></programlisting>
<para>Similarly, rules allowing traffic from the firewall to zone3:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST
# PORT(S)
ACCEPT col <emphasis role="bold">zone3</emphasis> tcp 22 ; mark=<emphasis
role="bold">fw</emphasis></programlisting>
<para>The important point here is that, when ZONE_BITS is non-zero, you
are allowed to place zone names in the MARK column. Shorewall will
automatically replae the name with the zone's mark value.</para>
<para>Suppose that you want to forward tcp port 80 to 192.168.4.45 in
zone3:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/ MARK
# PORT(S) PORT(S) DEST LIMIT GROUP
DNAT- net loc:172.168.4.45 tcp 80
ACCEPT col zone3:172.168.4.45 tcp 80 - - - - <emphasis
role="bold">net</emphasis></programlisting>
<para>Rules allowing traffic from the <emphasis
role="bold">zonei</emphasis> zones to the <emphasis
role="bold">net</emphasis> zone look like this: </para>
<programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/ MARK
# PORT(S) PORT(S) DEST LIMIT GROUP
ACCEPT loc net tcp 21 - - - - <emphasis
role="bold">zone1</emphasis></programlisting>
<para>And to the firewall:</para>
<programlisting>#ACTION SOURCE DEST PROTO DEST SOURCE ORIGINAL RATE USER/ MARK
# PORT(S) PORT(S) DEST LIMIT GROUP
ACCEPT zone2 col tcp - - - - <emphasis
role="bold">zone2</emphasis></programlisting>
</section>
<section id="Limitations">
<title>Limitations</title>

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12
manpages/shorewall-blrules.xml
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@ -59,6 +59,18 @@
rule. Must be one of the following.</para>
<variablelist>
<varlistentry>
<term>blacklog</term>
<listitem>
<para>May only be used if BLACKLIST_LOGLEVEL is specified in
<ulink url="shorewall.conf.html">shorewall.conf </ulink>(5).
Logs, audits (if specified) and applies the
BLACKLIST_DISPOSITION specified in <ulink
url="shorewall.conf.html">shorewall.conf</ulink> (5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">ACCEPT|CONTINUE|WHITELIST</emphasis></term>

16
manpages/shorewall.conf.xml
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@ -332,9 +332,11 @@
AUDIT_TARGET in the kernel and iptables.</para>
<para>The BLACKLIST_DISPOSITION setting has no effect on entries in
the <ulink url="shorewall-blrules.html">shorewall-blrules</ulink>
(5) file or in the BLACKLIST section of <ulink
url="shorewall-rules.html">shorewall-rules</ulink> (5).</para>
the BLACKLIST section of <ulink
url="shorewall-rules.html">shorewall-rules</ulink> (5). It
determines the disposition of packets sent to the <emphasis
role="bold">blacklog</emphasis> target of <ulink
url="shorewall-blrules.html">shorewall-blrules </ulink>(5).</para>
</listitem>
</varlistentry>
@ -349,9 +351,11 @@
BLACKLIST_LOGLEVEL=debug). If you do not assign a value or if you
assign an empty value then packets from blacklisted hosts are not
logged. The BLACKLIST_LOGLEVEL setting has no effect on entries in
the <ulink url="shorewall-blrules.html">shorewall-blrules</ulink>
(5) file or in the BLACKLIST section of <ulink
url="shorewall-rules.html">shorewall-rules</ulink> (5).</para>
the BLACKLIST section of <ulink
url="shorewall-rules.html">shorewall-rules</ulink> (5). It
determines the log level of packets sent to the <emphasis
role="bold">blacklog</emphasis> target of <ulink
url="shorewall-blrules.html">shorewall-blrules</ulink>(5).</para>
</listitem>
</varlistentry>

12
manpages6/shorewall6-blrules.xml
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@ -60,6 +60,18 @@
rule. Must be one of the following.</para>
<variablelist>
<varlistentry>
<term>blacklog</term>
<listitem>
<para>May only be used if BLACKLIST_LOGLEVEL is specified in
<ulink url="shorewall6.conf.html">shorewall6.conf </ulink>(5).
Logs, audits (if specified) and applies the
BLACKLIST_DISPOSITION specified in <ulink
url="shorewall6.conf.html">shorewall6.conf</ulink> (5).</para>
</listitem>
</varlistentry>
<varlistentry>
<term><emphasis
role="bold">ACCEPT|CONTINUE|WHITELIST</emphasis></term>

18
manpages6/shorewall6.conf.xml
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@ -262,10 +262,12 @@
be dropped or REJECT if the packets are to be replied with an ICMP
port unreachable reply or a TCP RST (tcp only). If you do not assign
a value or if you assign an empty value then DROP is assumed. The
BLACKLIST_DISPOSITION setting has no effect on entries in the <ulink
url="???">shorewall-blrules</ulink> (5) file or in the BLACKLIST
section of <ulink
url="shorewall6-rules.html">shorewall6-rules</ulink> (5).</para>
BLACKLIST_DISPOSITION setting has no effect on entries in the
BLACKLIST section of <ulink
url="shorewall6-rules.html">shorewall6-rules</ulink> (5). It
determines the disposition of packets sent to the <emphasis
role="bold">blacklog</emphasis> target of <ulink
url="shorewall6-blrules.html">shorewall6-blrules</ulink>(5).</para>
</listitem>
</varlistentry>
@ -280,9 +282,11 @@
BLACKLIST_LOGLEVEL=debug). If you do not assign a value or if you
assign an empty value then packets from blacklisted hosts are not
logged. The BLACKLIST_LOGLEVEL setting has no effect on entries in
the <ulink url="???">shorewall-blrules</ulink> (5) file and in the
BLACKLIST section of <ulink
url="shorewall6-rules.html">shorewall6-rules</ulink> (5).</para>
the BLACKLIST section of <ulink
url="shorewall6-rules.html">shorewall6-rules</ulink> (5). It
determines the log level of packets sent to the <emphasis
role="bold">blacklog</emphasis> target of <ulink
url="shorewall6-blrules.html">shorewall6-blrules</ulink>(5).</para>
</listitem>
</varlistentry>